Polishing composition and method utilizing abrasive particles treated with an aminosilane

ABSTRACT

The inventive method comprises chemically-mechanically polishing a substrate with an inventive polishing composition comprising a liquid carrier and abrasive particles that have been treated with a compound.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 14/657,594 file Mar. 13, 2015, which is a division of U.S.patent application Ser. No. 12/234,237, filed Sep. 19, 2008, now U.S.Pat. No. 9,028,572, and claims the benefit of U.S. Provisional PatentApplication No. 60/974,328, filed Sep. 21, 2007, which is incorporatedby reference.

BACKGROUND OF THE INVENTION

Compositions and methods for polishing (e.g., planarizing) the surfaceof a substrate are well known in the art. Polishing compositions (alsoknown as polishing slurries, CMP slurries, and CMP compositions)typically contain an abrasive material in an aqueous solution and areapplied to a surface by contacting the surface with a polishing padsaturated with the polishing composition. Typical abrasive materialsinclude metal oxide particles, such as silicon dioxide, cerium oxide,aluminum oxide, zirconium oxide, and tin oxide. U.S. Pat. No. 5,527,423,for example, describes a method for chemically-mechanically polishing(CMP) a metal layer by contacting the surface with a polishingcomposition comprising high purity fine metal oxide particles in anaqueous medium. The polishing composition is typically used inconjunction with a polishing pad (e.g., polishing cloth or disk).Suitable polishing pads are described in U.S. Pat. Nos. 6,062,968,6,117,000, and 6,126,532, which disclose the use of sinteredpolyurethane polishing pads having an open-celled porous network, andU.S. Pat. No. 5,489,233, which discloses the use of solid polishing padshaving a surface texture or pattern.

A semiconductor wafer typically includes a substrate, such as silicon orgallium arsenide, on which a plurality of transistors have been formed.Transistors are chemically and physically connected to the substrate bypatterning regions in the substrate and layers on the substrate. Thetransistors and layers are separated by interlevel dielectrics (ILDs),comprised primarily of some form of silicon oxide (SiO₂). Thetransistors are interconnected through the use of well-known multilevelinterconnects. Typical multilevel interconnects are comprised of stackedthin-films consisting of one or more of the following materials:titanium (Ti), titanium nitride (TiN), tantalum (Ta), aluminum-copper(Al—Cu), aluminum-silicon (Al—Si), copper (Cu), tungsten (W), dopedpolysilicon (poly-Si), and various combinations thereof. In addition,transistors or groups of transistors are isolated from one another,often through the use of trenches filled with an insulating materialsuch as silicon dioxide, silicon nitride, and/or polysilicon.

Chemical-mechanical polishing is used to planarize the surface of themetal layers or thin-films during the various stages of devicefabrication. Many of the known CMP compositions are suitable for limitedpurposes. However, the conventional CMP compositions tend to exhibitunacceptable polishing rates and selectivity levels with respect toinsulator materials used in wafer manufacture. In addition, many CMPcompositions tend to exhibit poor film removal traits for the underlyingfilms or produce deleterious film-corrosion, which leads to poormanufacturing yields.

As the technology for integrated circuit devices advances, traditionalmaterials are being used in new and different ways to achieve the levelof performance needed for advanced integrated circuits. In particular,silicon nitride and silicon oxide are being used in various combinationsto achieve new and ever more complex device configurations. In general,the structural complexity and performance characteristics vary acrossdifferent applications. There is an ongoing need for methods andcompositions that allow for the removal rates of various layers (e.g.,silicon nitride, silicon oxide) to be adjusted or tuned during CMP tomeet the polishing requirements for particular devices. The presentinvention provides such improved polishing methods and compositions.These and other advantages of the invention, as well as additionalinventive features, will be apparent from the description of theinvention provided herein.

BRIEF SUMMARY OF THE INVENTION

The invention provides a method of chemically-mechanically polishing asubstrate, which method comprises (i) contacting a substrate with achemical-mechanical polishing composition comprising (a) a liquidcarrier (b) an abrasive suspended in the liquid carrier, wherein theabrasive comprises metal oxide particles having a surface which has beentreated with a compound selected from the group consisting of anaminosilane compound, a phosphononiumsilane compound, and a sulfoniumsilane compound, and (c) an acid selected from the group consisting of aphosphonic acid and a boron containing acid, (ii) moving the polishingcomposition relative to the substrate, and (iii) abrading at least aportion of the substrate to polish the substrate.

The invention also provides a method of chemically-mechanicallypolishing a substrate, which method comprises (i) contacting a substratewith a chemical-mechanical polishing composition comprising (a) a liquidcarrier and (b) an abrasive suspended in the liquid carrier, wherein theabrasive comprises metal oxide particles having a surface which has beentreated with a compound selected from the group consisting of quaternaryaminosilane compounds, dipodal aminosilane compounds, and combinationsthereof, (ii) moving the polishing composition relative to thesubstrate, and (iii) abrading at least a portion of the substrate topolish the substrate.

The invention further provides a chemical-mechanical polishingcomposition for polishing a substrate comprising (a) a liquid carrier,(b) an abrasive suspended in the liquid carrier, wherein the abrasivecomprises metal oxide particles having a surface which has been treatedwith a compound selected from the group consisting of an aminosilanecompound, a phosphononiumsilane compound, and a sulfonium silanecompound, and (c) an acid selected from the group consisting of aphosphonic acid and a boron containing acid.

The invention additionally provides a chemical-mechanical polishingcomposition for polishing a substrate comprising (a) a liquid carrierand (b) an abrasive suspended in the liquid carrier, wherein theabrasive comprises metal oxide particles having a surface which has beentreated with an aminosilane compound selected from the group consistingof quaternary aminosilane compounds, dipodal aminosilane compounds, andcombinations thereof.

The invention also comprises a chemical-mechanical polishing compositionfor polishing a substrate comprising a liquid carrier, and an abrasivesuspended in the liquid carrier, wherein the abrasive comprises metaloxide particles having a surface which has been treated with a compoundselected from the group consisting of an aminosilane compound, aphosphoniumsilane compound, and a sulfonium silane compound, wherein thetreated abrasive particles have a surface coverage of the availablesilanols of about 2% to about 50%.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a chemical-mechanical polishing composition aswell as a method of chemically-mechanically polishing a substrate. Thepolishing composition comprises (a) a liquid carrier and (b) an abrasivesuspended in the liquid carrier, wherein the abrasive comprises metaloxide particles having a surface which has been treated with a compoundselected from the group consisting of an aminosilane compound such asaminosilane compounds, dipodal aminosilane compounds,phosphononiumsilane compounds, sulfonium silane compounds, andcombinations thereof. The composition can also comprise an acid selectedfrom the group consisting of a phosphonic acid and a boron containingacid. Further, the composition can comprise treated abrasive particleswherein the particles have a surface coverage of the available silanolsof about 2% to about 50%. The method comprises contacting a substratewith the chemical-mechanical polishing composition, moving the polishingcomposition relative to the substrate, and abrading at least a portionof the substrate to polish the substrate.

The polishing method can further comprise contacting the substrate witha polishing pad (e.g., polishing surface), which is moved relative tothe substrate with the polishing composition therebetween. The polishingpad can be any suitable polishing pad, many of which are known in theart. Suitable polishing pads include, for example, woven and non-wovenpolishing pads. Moreover, suitable polishing pads can comprise anysuitable polymer or combination of polymers of varying density,hardness, thickness, compressibility, ability to rebound uponcompression, and compression modulus. Suitable polymers include, forexample, polyvinylchloride, polyvinylfluoride, nylon, fluorocarbon,polycarbonate, polyester, polyacrylate, polyether, polyethylene,polyamide, polyurethane, polystyrene, polypropylene, coformed productsthereof, and mixtures thereof.

The polishing pad can comprise fixed abrasive particles on or within thepolishing surface of the polishing pad, or the polishing pad can be freeor substantially free of fixed abrasive particles. Fixed abrasivepolishing pads include pads having abrasive particles affixed to thepolishing surface of the polishing pad by way of an adhesive, binder,ceramer, resin, or the like or abrasives that have been impregnatedwithin a polishing pad so as to form an integral part of the polishingpad, such as, for example, a fibrous batt impregnated with anabrasive-containing polyurethane dispersion.

The polishing pad can have any suitable configuration. For example, thepolishing pad can be circular and, when in use, typically will have arotational motion about an axis perpendicular to the plane defined bythe surface of the pad. The polishing pad can be cylindrical, thesurface of which acts as the polishing surface, and, when in use,typically will have a rotational motion about the central axis of thecylinder. The polishing pad can be in the form of an endless belt,which, when in use, typically will have a linear motion with respect tothe cutting edge being polished. The polishing pad can have any suitableshape and, when in use, have a reciprocating or orbital motion along aplane or a semicircle. Many other variations will be readily apparent tothe skilled artisan.

The polishing composition comprises an abrasive, which desirably issuspended in the liquid carrier (e.g., water). The abrasive typically isin particulate form. Preferably, the abrasive comprises, consistsessentially of, or consists of silica particles, especially colloidalsilica particles. Colloidal silica particles are prepared via a wetprocess and typically are non-aggregated, individually discreteparticles, which generally are spherical or nearly spherical in shape,but can have other shapes (e.g., shapes with generally elliptical,square, or rectangular cross-sections). Such particles typically arestructurally different from fumed particles, which are prepared via apyrogenic or flame hydrolysis process and are chain-like structures ofaggregated primary particles.

Preferably, the colloidal silica is precipitated orcondensation-polymerized silica, which can be prepared using any methodknown to those of ordinary skill in the art, such as by the sol gelmethod or by silicate ion-exchange. Condensation-polymerized silicaparticles typically are prepared by condensing Si(OH)₄ to formsubstantially spherical particles. The precursor Si(OH)₄ can beobtained, for example, by hydrolysis of high purity alkoxysilanes, or byacidification of aqueous silicate solutions. Such abrasive particles canbe prepared in accordance with U.S. Pat. No. 5,230,833 or can beobtained as any of various commercially available products such as theBINDZIL 50/80, 30/310, and 40/130 products from EKA Chemicals, the FusoPL-1, PL-2, PL-3, and PL-3H products, and the Nalco 1034A, 1050, 2327,and 2329 products, as well as other similar products available fromDuPont, Bayer, Applied Research, Nissan Chemical (the SNOWTEX products),and Clariant.

The particle size of a particle is the diameter of the smallest spherethat encompasses the particle. The abrasive particles can have anysuitable particle size. The abrasive particles have an average particlesize of about 5 nm or more (e.g., about 10 nm or more, about 15 nm ormore, about 20 nm or more, or about 30 nm or more). The abrasiveparticles can have an average particle size of about 150 nm or less(e.g., about 130 nm or less, about 80 nm or less, about 50 nm or less,or about 30 nm or less). Accordingly, the abrasive particles can have anaverage particle size of about 10 nm to about 150 nm (e.g., about 20 nmto about 130 nm, about 15 nm to about 100 nm, about 20 nm to about 80nm, or about 20 nm to about 60 nm).

Any suitable amount of abrasive can be present in the polishingcomposition. Typically, about 0.01 wt. % or more (e.g., about 0.05 wt. %or more) abrasive will be present in the polishing composition. Moretypically, about 0.1 wt. % or more (e.g., about 0.2 wt. % or more, about0.3 wt. % or more, about 0.6 wt. % or more, about 1 wt. % or more, orabout 2 wt. % or more) abrasive will be present in the polishingcomposition. The amount of abrasive in the polishing compositiontypically will be about 30 wt. % or less, more typically will be about20 wt. % or less (e.g., about 15 wt. % or less, about 10 wt. % or less,about 5 wt. % or less, about 3 wt. % or less, or about 2 wt. % or less).Preferably, the amount of abrasive in the polishing composition is about0.01 wt. % to about 20 wt. %, and more preferably about 0.05 wt. % toabout 15 wt. % (e.g., about 0.1 wt. % to about 10 wt. %, about 0.1 wt. %to about 5 wt. %, about 0.1 wt. % to about 3 wt. %, about 0.1 wt. % toabout 2 wt. %, or about 0.2 wt. % to about 2 wt. %).

The abrasive is treated with at least one silane compound, aminosilanecompound, phosphononiumsilane compound, or sulfonium silane compound.Suitable silane compounds include primary aminosilanes, secondaryaminosilanes, tertiary aminosilanes, quaternary aminosilanes, anddipodal aminosilanes. The aminosilane compound can be any suitableaminosilane, such as aminopropyl trialkoxysilane,bis(2-hydroxyethyl)-3-aminopropyl trialkoxysilane,diethylaminomethyltrialkoxysilane, (N,N-diethyl-3-aminopropyl)trialkoxysilane), 3-(N-styrylmethyl-2-aminoethylaminopropyltrialkoxysilane, (2-N-benzylaminoethyl)-3-aminopropyl trialkoxysilane),trialkoxysilyl propyl-N,N,N-trimethyl ammonium chloride,N-(trialkoxysilylethyl)benzyl-N,N,N-trimethyl ammonium chloride,(bis(methyldialkoxysilylpropyl)-N-methyl amine,bis(trialkoxysilylpropyl) urea,bis(3-(trialkoxysily)propyl)-ethylenediamine, andbis(trialkoxysilylpropyl)amine. The alkoxy groups in the aboveaminosilane coumpounds can be substituted by other hydrolizable groupssuch as halides, amines and carboxylates. Preferably, the silane isdipodal or tripodal. The choice of silane compound depends, in part, onthe type of substrate that is being polished.

Preferably, the treated abrasive particles have a particle size which isthe same as or slightly larger than the untreated abrasive particles.Any increase in particle size of the treated abrasive particles ispreferably about 2 times that of the untreated particles or less (e.g.,about 1.7 times that of the untreated particles or less, about 1.4 timesthat of the untreated particles or less, or about 1.2 times that of theuntreated particles or less). For example, the treated abrasiveparticles have an average particle size of about 5 nm or more (e.g.,about 10 nm or more, about 15 nm or more, about 20 nm or more, or about30 nm or more). The treated abrasive particles can have an averageparticle size of about 150 nm or less (e.g., about 130 nm or less, about80 nm or less, about 50 nm or less, or about 30 nm or less).Accordingly, the treated abrasive particles can have an average particlesize of about 10 nm to about 150 nm (e.g., about 20 nm to about 130 nm,about 15 nm to about 100 nm, about 20 nm to about 80 nm, or about 20 nmto about 60 nm).

Any suitable method of treating the abrasive, many of which are known tothose of ordinary skill in the art, can be used. For example, theabrasive can be treated with the aminosilane compound before mixing withthe other components of the polishing composition, or the aminosilaneand the abrasive can be added simultaneously to some or all of the othercomponents of the polishing composition.

It is preferred that the silane with which the particle is treated doesnot cover all of the available silanol sites on the particle. Typically,the treated abrasive particles have a surface coverage of the availablesilanols of about 2% or more (e.g., about 4% or more, about 8% or more).The treated abrasive particles preferably have a surface coverage of theavailable silanols of about 50% or less (e.g., about 30% or less, about20% or less, or about 10% or less). Preferably, the treated abrasiveparticles have a surface coverage of the available silanols of about 2%to about 50% (e.g., about 2% to about 30%, about 2% to about 20%, orabout 4% to about 15%). The surface silanol concentration can beestimated using a typical value of 5 SiOH/nm² for silica and the BETsurface area of the silica.

The aminosilane compound can be present in the polishing composition inany suitable amount. Typically, the polishing composition comprisesabout 30 ppm or more (e.g., about 50 ppm or more, about 100 ppm or more,about 200 ppm or more, about 300 ppm or more, about 400 ppm or more, orabout 500 ppm or more) aminosilane compound. The polishing compositionpreferably comprises about 2000 ppm or less (e.g., about 1000 ppm orless, about 800 ppm or less, or about 600 ppm or less) aminosilanecompound. Preferably, the polishing composition comprises about 50 ppmto about 2000 ppm (e.g., about 100 ppm to about 1000 ppm, about 200 ppmto about 800 ppm, about 250 ppm to about 700 ppm, or about 275 ppm toabout 600 ppm) aminosilane compound.

The zeta potential of a particle refers to the difference between theelectrical charge of the ions surrounding the particle and theelectrical charge of the bulk solution (e.g., the liquid carrier and anyother components dissolved therein). If the abrasive is silica, beforethe abrasive is treated with the aminosilane compound, it has a zetapotential of zero at a pH of about 2 to about 3. After treatment withthe aminosilane compound, the treated abrasive particles has a positivecharge, and thus a positive zeta potential. Typically, the treatedabrasive particles have a zeta potential of about 5 mV or more (e.g.,about 10 mV or more, about 15 mV or more, about 20 mV or more, about 25mV or more, or about 30 mV or more). The treated abrasive particlespreferably have a zeta potential of about 50 mV or less (e.g., about 45mV or less, about 40 mV or less, or about 35 mV or less). Preferably,the treated abrasive particles have a zeta potential of about 5 mV toabout 50 mV (e.g., about 10 mV to about 45 mV, about 15 mV to about 40mV, or about 20 mV to about 40 mV).

A liquid carrier is used to facilitate the application of the abrasiveand any optional additives to the surface of a suitable substrate to bepolished (e.g., planarized). The liquid carrier can be any suitablecarrier (e.g., solvent) including lower alcohols (e.g., methanol,ethanol, etc.), ethers (e.g., dioxane, tetrahydrofuran, etc.), water,and mixtures thereof. Preferably, the liquid carrier comprises, consistsessentially of, or consists of water, more preferably deionized water.

The polishing composition also may contain an acid, which can be anysuitable acid. The acid used will depend, in part, on the type ofsubstrate being polished. For example, the acid can be phthalic acid,nitric acid, a boron-containing acid such as boric acid, or aphosphorus-containing acid, such as 1-hydroxyethylidene-1,1-diphosphonicacid (e.g., DEQUEST 2010), amino tri(methylene phosphonic acid) (e.g.,DEQUEST 2000), phosphoric acid, or combinations thereof. The acid can bepresent in the polishing composition in any suitable amount. Typically,the polishing composition comprises about 10 ppm or more (e.g., about 20ppm or more, about 30 ppm or more, about 50 ppm or more, about 100 ppmor more, about 150 ppm or more, about 300 ppm or more, or about 500 ppmor more) acid. The polishing composition preferably comprises about 3000ppm or less (e.g., about 2000 ppm or less, about 1500 ppm or less, orabout 1000 ppm or less) acid. Preferably, the polishing compositioncomprises about 10 ppm to about 3000 ppm (e.g., about 20 ppm to about2000 ppm, about 30 ppm to about 1500 ppm, about 50 ppm to about 1000ppm, or about 100 ppm to about 1000 ppm) acid. The preferred aciddepends, in part, on the pH of the polishing composition.

The polishing composition also may comprise an oxidizing agent, whichcan be any suitable oxidizing agent for one or more materials of thesubstrate to be polished with the polishing composition. Preferably, theoxidizing agent is selected from the group consisting of bromates,bromites, chlorates, chlorites, hydrogen peroxide, hypochlorites,iodates, hydroxylamine salts, monoperoxy sulfate, monoperoxy sulfite,monoperoxyphosphate, monoperoxyhypophosphate, monoperoxypyrophosphate,organo-halo-oxy compounds, periodates, permanganate, peroxyacetic acid,and mixtures thereof. The oxidizing agent can be present in thepolishing composition in any suitable amount. Typically, the polishingcomposition comprises about 0.01 wt. % or more (e.g., about 0.02 wt. %or more, about 0.1 wt. % or more, about 0.5 wt. % or more, or about 1wt. % or more) oxidizing agent. The polishing composition preferablycomprises about 20 wt. % or less (e.g., about 15 wt. % or less, about 10wt. % or less, or about 5 wt. % or less) oxidizing agent. Preferably,the polishing composition comprises about 0.01 wt. % to about 20 wt. %(e.g., about 0.05 wt. % to about 15 wt. %, about 0.1 wt. % to about 10wt. %, about 0.3 wt. % to about 6 wt. %, or about 0.5 wt. % to about 4wt. %) oxidizing agent.

The polishing composition, specifically the liquid carrier with anycomponents dissolved or suspended therein, can have any suitable pH. Thepolishing composition can have a pH of less than about 9 (e.g., about 8or less, about 7 or less, about 6 or less, about 5 or less, about 4.5 orless, or about 4 or less). The polishing composition can have a pH ofabout 1 or more (e.g., about 1.5 or more, about 3 or more, about 4 ormore, about 5 or more, about 7 or more, or about 8 or more). The pH canbe, for example, from about 1 to about 7 (e.g., from about 1.5 to about6, from about 1.5 to about 5, or from about 2 to about 4). The pH canbe, for example, from about 3 to about 8 (e.g., from about 3.5 to about6, or from about 4.5 to about 6.5). The pH can be, for example, fromabout 7 to about 9 (e.g., from about 7.5 to about 8.5).

The pH of the polishing composition can be achieved and/or maintained byany suitable means. More specifically, the polishing composition canfurther comprise a pH adjustor, a pH buffering agent, or a combinationthereof. The pH adjustor can comprise, consist essentially of, orconsist of any suitable pH-adjusting compound. For example, the pHadjustor can be the acid of the polishing composition. The pH bufferingagent can be any suitable buffering agent, for example, phosphates,acetates, borates, sulfonates, carboxylates, ammonium salts, aminoacids, and the like. The capability of a buffering agent depends onfactors such as its pKa, (negative logarithm of the acid dissociationconstant) and concentration. For optimal buffering it is preferred thatthe buffering agent has a pKa within about 1 unit of the pH of thepolishing composition. The polishing composition can comprise anysuitable amount of a pH adjustor and/or a pH buffering agent, providedsuch amount is sufficient to achieve and/or maintain the desired pH ofthe polishing composition, e.g., within the ranges set forth herein.

It is preferred that the polishing composition has low conductivity.Conductivity is the property of a substance that describes its abilityto transfer electricity. In electrolytic solutions, the current iscarried by the ions in solution such as acids, bases and salts. Theconductivity in the polishing composition preferably is about 1500 μS/cmor less (e.g., about 900 μS/cm or less, about 600 μS/cm or less, orabout 300 μS/cm or less). The conductivity in the polishing compositionpreferably is about 30 μS/cm or more (e.g., about 60 μS/cm or more,about 100 μS/cm or more). Preferably, the conductivity in the polishingcomposition preferably is about 30 μS/cm to about 1500 μS/cm (e.g.,about 30 μS/cm to about 900 μS/cm, about 60 μS/cm to about 600 μS/cm).

The polishing composition optionally comprises a corrosion inhibitor(i.e., a film-forming agent). The corrosion inhibitor can comprise,consist essentially of, or consist of any suitable corrosion inhibitor.Preferably, the corrosion inhibitor is an azole compound. The amount ofcorrosion inhibitor used in the polishing composition typically is about0.0001 wt. % to about 3 wt. % (preferably about 0.001 wt. % to about 2wt. %) based on the total weight of the polishing composition.

The polishing composition optionally comprises a chelating or complexingagent. The complexing agent is any suitable chemical additive thatenhances the removal rate of the substrate layer being removed, or thatremoves trace metal contaminants in silicon polishing. Suitablechelating or complexing agents can include, for example, carbonylcompounds (e.g., acetylacetonates and the like), simple carboxylates(e.g., acetates, aryl carboxylates, and the like), carboxylatescontaining one or more hydroxyl groups (e.g., glycolates, lactates,gluconates, gallic acid and salts thereof, and the like), di-, tri-, andpoly-carboxylates (e.g., oxalates, oxalic acid, phthalates, citrates,succinates, tartrates, malates, edetates (e.g., dipotassium EDTA),mixtures thereof, and the like), carboxylates containing one or moresulfonic and/or phosphonic groups, and the like. Suitable chelating orcomplexing agents also can include, for example, di-, tri-, orpolyalcohols (e.g., ethylene glycol, pyrocatechol, pyrogallol, tannicacid, and the like), and amine-containing compounds (e.g., ammonia,amino acids, amino alcohols, di-, tri-, and polyamines, and the like).The choice of chelating or complexing agent will depend on the type ofsubstrate layer being removed.

It will be appreciated that many of the aforementioned compounds canexist in the form of a salt (e.g., a metal salt, an ammonium salt, orthe like), an acid, or as a partial salt. For example, citrates includecitric acid, as well as mono-, di-, and tri-salts thereof; phthalatesinclude phthalic acid, as well as mono-salts (e.g., potassium hydrogenphthalate) and di-salts thereof; perchlorates include the correspondingacid (i.e., perchloric acid), as well as salts thereof. Furthermore,certain compounds or reagents may perform more than one function. Forexample, some compounds can function both as a chelating agent and anoxidizing agent (e.g., certain ferric nitrates and the like).

The polishing composition optionally further comprises one or more otheradditives. Such additives include acrylates comprising one or moreacrylic subunits (e.g., vinyl acrylates and styrene acrylates), andpolymers, copolymers, and oligomers thereof, and salts thereof.

The polishing composition can comprise a surfactant and/or rheologicalcontrol agent, including viscosity enhancing agents and coagulants(e.g., polymeric rheological control agents, such as, for example,urethane polymers). Suitable surfactants can include, for example,cationic surfactants, anionic surfactants, nonionic surfactants,amphoteric surfactants, mixtures thereof, and the like. Preferably, thepolishing composition comprises a nonionic surfactant. Preferrednonionic surfactants contain a polyether moiety. One example of asuitable nonionic surfactant is an ethylenediamine polyoxyethylenesurfactant. The amount of surfactant in the polishing compositiontypically is about 0.0001 wt. % to about 1 wt. % (preferably about 0.001wt. % to about 0.1 wt. %, and more preferably about 0.005 wt. % to about0.05 wt. %).

The polishing composition can comprise an antifoaming agent. Theantifoaming agent can comprise, consist essentially of, or consist ofany suitable anti-foaming agent. Suitable antifoaming agents include,but are not limited to, silicon-based and acetylenic diol-basedantifoaming agents. The amount of anti-foaming agent in the polishingcomposition typically is about 10 ppm to about 140 ppm.

The polishing composition can comprise a biocide. The biocide cancomprise, consist essentially of, or consist of any suitable biocide,for example an isothiazolinone biocide. The amount of biocide in thepolishing composition typically is about 1 to about 50 ppm, preferablyabout 10 to about 20 ppm.

The polishing composition preferably is colloidally stable. The termcolloid refers to the suspension of the particles in the liquid carrier.Colloidal stability refers to the maintenance of that suspension throughtime. A polishing composition is considered colloidally stable if, whenthe polishing composition is placed into a 100 ml graduated cylinder andallowed to stand unagitated for a time of 2 hours, the differencebetween the concentration of particles in the bottom 50 ml of thegraduated cylinder ([B] in terms of g/ml) and the concentration ofparticles in the top 50 ml of the graduated cylinder ([T] in terms ofg/ml) divided by the initial concentration of particles in the polishingcomposition ([C] in terms of g/ml) is less than or equal to 0.5 (i.e.,{[B]−[T]}/[C]≦0.5). Preferably, the value of [B]−[T]/[C] is less than orequal to 0.3, more preferably is less than or equal to 0.1, even morepreferably is less than or equal to 0.05, and most preferably is lessthan or equal to 0.01.

The polishing composition can be prepared by any suitable technique,many of which are known to those skilled in the art. The polishingcomposition can be prepared in a batch or continuous process. Generally,the polishing composition can be prepared by combining the componentsthereof in any order. The term “component” as used herein includesindividual ingredients (e.g., liquid carrier, abrasive, acid, etc.) aswell as any combination of ingredients (e.g., water, treated abrasives,surfactants, etc.).

The polishing composition can be supplied as a one-package systemcomprising a liquid carrier, and optionally an abrasive and/or otheradditives. Alternatively, some of the components, such as an oxidizingagent, can be supplied in a first container, either in dry form, or as asolution or dispersion in the liquid carrier, and the remainingcomponents, such as the abrasive and other additives, can be supplied ina second container or multiple other containers. Other two-container, orthree or more container combinations of the components of the polishingcomposition are within the knowledge of one of ordinary skill in theart.

Solid components, such as an abrasive, can be placed in one or morecontainers either in dry form or as a solution in the liquid carrier.Moreover, it is suitable for the components in the first, second, orother containers to have different pH values, or alternatively to havesubstantially similar, or even equal, pH values. The components of thepolishing composition can be partially or entirely supplied separatelyfrom each other and can be combined, e.g., by the end-user, shortlybefore use (e.g., 1 week or less prior to use, 1 day or less prior touse, 1 hour or less prior to use, 10 minutes or less prior to use, or 1minute or less prior to use).

The polishing composition also can be provided as a concentrate which isintended to be diluted with an appropriate amount of liquid carrierprior to use. In such an embodiment, the polishing compositionconcentrate can comprise a liquid carrier, and optionally othercomponents in amounts such that, upon dilution of the concentrate withan appropriate amount of liquid carrier, each component will be presentin the polishing composition in an amount within the appropriate rangerecited above for each component. For example, each component can bepresent in the concentrate in an amount that is about 2 times (e.g.,about 3 times, about 4 times, or about 5 times) greater than theconcentration recited above for each component in the polishingcomposition so that, when the concentrate is diluted with an appropriatevolume of liquid carrier (e.g., an equal volume of liquid carrier, 2equal volumes of liquid carrier, 3 equal volumes of liquid carrier, or 4equal volumes of liquid carrier, respectively), each component will bepresent in the polishing composition in an amount within the ranges setforth above for each component. Furthermore, as will be understood bythose of ordinary skill in the art, the concentrate can contain anappropriate fraction of the liquid carrier present in the finalpolishing composition in order to ensure that the polyether amine andother suitable additives, such as an abrasive, are at least partially orfully dissolved or suspended in the concentrate.

The inventive method of polishing a substrate is particularly suited foruse in conjunction with a chemical-mechanical polishing (CMP) apparatus.Typically, the apparatus comprises a platen, which, when in use, is inmotion and has a velocity that results from orbital, linear, or circularmotion, a polishing pad in contact with the platen and moving with theplaten when in motion, and a carrier that holds a substrate to bepolished by contacting and moving relative to the surface of thepolishing pad. The polishing of the substrate takes place by thesubstrate being placed in contact with the polishing pad and thepolishing composition of the invention (which generally is disposedbetween the substrate and the polishing pad), with the polishing padmoving relative to the substrate, so as to abrade at least a portion ofthe substrate to polish the substrate.

Desirably, the CMP apparatus further comprises an in situ polishingendpoint detection system, many of which are known in the art.Techniques for inspecting and monitoring the polishing process byanalyzing light or other radiation reflected from a surface of theworkpiece are known in the art. Desirably, the inspection or monitoringof the progress of the polishing process with respect to a substratebeing polished enables the determination of the polishing end-point,i.e., the determination of when to terminate the polishing process withrespect to a particular substrate. Such methods are described, forexample, in U.S. Pat. No. 5,196,353, U.S. Pat. No. 5,433,651, U.S. Pat.No. 5,609,511, U.S. Pat. No. 5,643,046, U.S. Pat. No. 5,658,183, U.S.Pat. No. 5,730,642, U.S. Pat. No. 5,838,447, U.S. Pat. No. 5,872,633,U.S. Pat. No. 5,893,796, U.S. Pat. No. 5,949,927, and U.S. Pat. No.5,964,643.

Polishing refers to the removal of at least a portion of a surface topolish the surface. Polishing can be performed to provide a surfacehaving reduced surface roughness by removing gouges, crates, pits, andthe like, but polishing also can be performed to introduce or restore asurface geometry characterized by an intersection of planar segments.

The substrate to be polished using the method of the invention can beany suitable substrate. Suitable substrates include, but are not limitedto, flat panel displays, integrated circuits, memory or rigid disks,metals, interlayer dielectric (ILD) devices, semiconductors,micro-electro-mechanical systems, ferroelectrics, and magnetic heads.The substrate can comprise multiple layers, e.g., an insulating layer, aconducting layer. The insulating layer can be a metal oxide, porousmetal oxide, glass, organic polymer, fluorinated organic polymer, or anyother suitable high or low-k insulating layer. The insulating layer cancomprise, consist of, or consist essentially of silicon oxide, siliconnitride, or combinations thereof. The silicon oxide can be any suitablesilicon oxide, many of which are known in the art. Suitable types ofsilicon oxide include but are not limited to borophosphosilicate glass(BPSG), plasma-enhanced tetraethyl ortho silicate (PETEOS), thermaloxide, undoped silicate glass, carbon doped silicon oxide (CDO),fluorine doped silicon oxide (FSG), and high density plasma (HDP) oxide.The substrate can further comprise at least one additional insulatinglayer. The at least one additional insulating layer can comprise,consist of, or consist essentially of silicon oxide, silicon nitride, orcombinations thereof. The substrate can further comprise a metal layer.The metal layer can comprise, consist essentially of, or consist of anysuitable metal, many of which are known in the art, such as, forexample, tungsten, tantalum, titanium, ruthenium, copper, aluminum.

The method of the invention is particularly useful in polishing asubstrate comprising at least one layer of silicon oxide. The siliconoxide layer can be removed at a rate of about 100 Å/min or more (e.g.,about 300 Å/min or more, about 400 Å/min or more, about 500 Å/min ormore, about 600 Å/min or more, or about 800 Å/min or more). The siliconoxide layer can be removed at a rate of about 5000 Å/min or less (e.g.,about 3000 Å/min or less, about 2000 Å/min or less, about 1000 Å/min orless, about 800 Å/min or less, or about 500 Å/min or less). Accordingly,the silicon oxide layer can be removed from the substrate at a rate ofabout 200 Å/min to about 5000 Å/min (e.g., about 300 Å/min to about 2000Å/min, about 600 Å/min to about 5000 Å/min, about 400 Å/min to about1500 Å/min, about 500 Å/min to about 1000 Å/min, or about 500 Å/min toabout 800 Å/min).

The method of the invention also is particularly useful in polishing asubstrate comprising at least one layer of silicon nitride. The siliconnitride layer can be removed at a rate of about 100 Å/min or more (e.g.,about 300 Å/min or more, about 400 Å/min or more, about 500 Å/min ormore, about 600 Å/min or more, or about 800 Å/min or more). The siliconnitride layer can be removed at a rate of about 3000 Å/min or less(e.g., about 2000 Å/min or less, about 1500 Å/min or less, about 1000Å/min or less, about 800 Å/min or less, or about 500 Å/min or less).Accordingly, the silicon nitride layer can be removed from the substrateat a rate of about 100 Å/min to about 3000 Å/min (e.g., about 100 Å/minto about 2000 Å/min, about 100 Å/min to about 1500 Å/min, about 200Å/min to about 1500 Å/min, about 300 Å/min to about 1000 Å/min, or about500 Å/min to about 800 Å/min).

The substrate can comprise at least one layer of silicon nitride and atleast one layer of silicon oxide, wherein the silicon oxide layer isselectively removed relative to the layer of silicon nitride, whereinthe silicon nitride layer is selectively removed relative to the layerof silicon oxide, or wherein the silicon nitride layer is removed at asimilar rate relative to the layer of silicon oxide.

The following examples further illustrate the invention but, of course,should not be construed as in any way limiting its scope. All data inthe following examples was generated on a Logitech polisher using an IC1000 pad and 1.6 inch wafers at a polishing downforce of 28 kPa (4 psi).

EXAMPLE 1

This example demonstrates the effect on the removal rate of siliconoxide and silicon nitride by the pH of a polishing compositioncontaining colloidal silica particles which have been treated with anaminosilane compound.

A TEOS wafer, a BPSG wafer, and a silicon nitride wafer were polishedwith ten different polishing compositions. Each polishing compositioncontained 1 wt. % colloidal silica that was treated with 300 ppmaminopropyl triethoxysilane. For polishing compositions 1A-1J, theaminopropyl triethoxysilane was mixed with water for 30 minutes, thenthe silica was added, and the resulting dispersion was stirred for 2hours. For polishing compositions 1G-1J, the pH was adjusted to 4 withnitric acid prior to the addition of the silane. The pH of eachpolishing composition was then adjusted to the target pH with nitricacid, except for polishing compositions 1A and 1G that did not containany additional nitric acid. The pH of each polishing composition isindicated in Table 1.

The silicon oxide removal rate (Å/min) for both the TEOS and BPSG wafersand the silicon nitride removal rate (Å/min) were determined for eachpolishing composition, and the results are shown in Table 1.

TABLE 1 Silicon Oxide Silicon Oxide Removal Rate Removal Rate SiliconNitride Polishing (Å/min) (Å/min) Removal Rate Composition pH (TEOS)(BPSG) (Å/min) 1A 8.33 1826 4048 40 1B 6.06 2282 4010 42 1C 4.91 22334259 16 1D 4.4 14 3759 11 1E 3.52 14 3743 7 1F 4.02 77 — 10 1G 5.73 1890— 104 1H 4.24 1343 — 20 1I 5.1 2217 — 41 1J 3.76 441 — 22

As is apparent from the data presented in Table 1, the pH of thepolishing composition can be adjusted to alter the polishing rate ofboth silicon oxide and silicon nitride.

EXAMPLE 2

This example demonstrates the effect on the removal rate of siliconoxide and silicon nitride by the pH of a polishing compositioncontaining acid and colloidal silica particles which have been treatedwith an aminosilane compound.

A TEOS wafer and a silicon nitride wafer were polished with twenty-twodifferent polishing compositions. Polishing compositions 2A-2M contained1 wt. % colloidal silica (50 nm) that was treated with 300 ppmaminopropyl triethoxysilane. Polishing compositions 2N-2Q contained 1wt. % colloidal silica that was untreated. Polishing compositions 2R-2Vcontained 1 wt. % colloidal silica (35 nm) treated with 250 ppmbis(trialkoxysilylpropyl)amine, 1% hydrogen peroxide, and nitric acid,which was used to adjust the pH to that indicated below in Table 2. ThepH of each polishing composition and the type and amount of acid thatwas added to each composition are indicated in Table 2.

The silicon oxide removal rate (Å/min) and the silicon nitride removalrate (Å/min) were determined for each polishing composition, and theresults are shown in Table 2.

TABLE 2 Silicon Oxide Silicon Nitride Polishing Acid Removal RateRemoval Rate Composition pH Concentration (Å/min) (Å/min) 2A 8.1 40 ppmDequest 1152 55 2010 2B 8.1 10 ppm 1215 63 phosphoric acid 2C 5 118 ppm1977 41 phosphoric acid 2D 3.5 183 ppm 26 25 phosphoric acid 2E 2.33 750ppm 23 47 phosphoric acid 2F 7.91 50 ppm Dequest 1322 77 2000 2G 4.96270 ppm 326 314 Dequest 2000 2H 3.92 250 ppm 258 486 Dequest 2000 2I2.35 1000 ppm 545 726 Dequest 2000 2J 7.95 38 ppm phthalic 1152 56 acid2K 3.85 291 ppm 75 16 phthalic acid 2L 2.92 790 ppm 4 9 phthalic acid 2M2.9 946 ppm 29 10 phthalic acid 2N 7.5 15 ppm nitric 8 0 acid 2O 5 20ppm nitric 31 1 acid 2P 3.5 60 ppm nitirc 84 368 acid 2Q 2.5 220 ppmnitric 380 62 acid 2R 6.0 300 ppm boric 1645 — acid 2S 5.0 300 ppm boric1198 — acid 2T 4.0 300 ppm boric 1174 — acid 2U 3.0 300 ppm boric 677 —acid 2V 2.2 300 ppm boric 381 — acid

As is apparent from the data presented in Table 2, the pH of thepolishing composition can be adjusted using several different acids toselectively remove either silicon oxide or silicon nitride.

EXAMPLE 3

This example demonstrates the effect on the removal rate of siliconoxide and silicon nitride by the pH and acid concentration of apolishing composition containing colloidal silica particles which havebeen treated with an aminosilane compound.

A TEOS wafer and a silicon nitride wafer were polished with fifteendifferent polishing compositions. Each of the polishing compositionscontained 1 wt. % colloidal silica that was treated with 300 ppmaminopropyl triethoxysilane. The pH of polishing compositions 3A-3D wasadjusted to 9 before the addition of the silane and the pH of polishingcompositions 3E-3O was 7.5 before the addition of the silane. The finalpH of each polishing composition and the amount of1-hydroxyethylidene-1,1-diphosphonic acid (DEQUEST 2010) that was addedto each composition are indicated in Table 3.

The silicon oxide removal rate (Å/min) and the silicon nitride removalrate (Å/min) were determined for each polishing composition, and theresults are shown in Table 3.

TABLE 3 Silicon Silicon DEQUEST Oxide Nitride 2010 Removal Removal ZetaPolishing Concentration Rate Rate Potential Composition pH (ppm) (Å/min)(Å/min) (mV) 3A 9.14 0 91 0 −27 3B 8.06 50 735 11 3 3C 7.21 100 998 7215 3D 6.64 150 1237 148 18 3E 8.43 0 331 39 35 3F 8.15 23 1008 24 35 3G7.43 49 859 48 35 3H 6.73 106 1104 109 36 3I 6.16 163 1378 167 34 3J5.13 196 1180 268 39 3K 4.09 223 1130 461 23 3L 3.05 272 800 575 31 3M2.81 372 1050 675 — 3N 2.5 820 652 759 — 3O 2.27 1578 543 809 —

As is apparent from the data presented in Table 3, the pH of theinventive polishing composition can be adjusted using differentconcentrations of acid to selectively remove either silicon oxide orsilicon nitride.

EXAMPLE 4

This example demonstrates the effect on the removal rate of siliconoxide and silicon nitride by a polishing composition containingcolloidal silica particles which have been treated with an aminosilanecompound and a phosphorus-containing acid.

A TEOS wafer and a silicon nitride wafer were polished with fourdifferent polishing compositions. Each of the polishing compositionscontained 3 wt. % colloidal silica that was treated with 800 ppmaminoalkyl siloxane. Nitric acid was added to polishing compositions 4Aand 4C to adjust the pH to 2.2. The pH of each polishing composition andthe type and amount of acid that was added to each composition areindicated in Table 4.

The silicon oxide removal rate (Å/min) and the silicon nitride removalrate (Å/min) were determined for each polishing composition, and theresults are shown in Table 4.

TABLE 4 Silicon Oxide Silicon Nitride Polishing Acid Removal RateRemoval Rate Composition pH Concentration (Å/min) (Å/min) 4A 2.2 7.28 mM605 970 DEQUEST 2000 4B 3.2 7.28 mM 1170 964 DEQUEST 2000 4C 2.2 7.28 mM539 1023 DEQUEST 2010 4D 3.2 7.28 mM 1620 989 DEQUEST 2010

As is apparent from the data presented in Table 4, the pH and type ofacid used in the polishing composition can be adjusted to selectivelyremove either silicon oxide or silicon nitride.

EXAMPLE 5

This example demonstrates the effect on the removal rate of siliconoxide and silicon nitride by a polishing composition containingcolloidal silica particles which have been treated with an aminosilanecompound.

A TEOS wafer and a silicon nitride wafer were polished with twelvedifferent polishing compositions. Each of the polishing compositionscontained colloidal silica that was treated with aminopropyltriethoxysilane and 1000 ppm 1-hydroxyethylidene-1,1-diphosphonic acid(DEQUEST 2010). The amount of aminopropyl triethoxysilane and colloidalsilica that were added to each composition and the pH of eachcomposition are indicated in Table 5.

The silicon oxide removal rate (Å/min) and silicon nitride removal rate(Å/min) were determined for each polishing composition, and the resultsare shown in Table 5.

TABLE 5 Aminopropyl Silicon Oxide Silicon Nitride Zeta Polishing Silicatriethoxysilane Removal Rate Removal Rate Potential Composition pH (wt.%) (ppm) (Å/min) (Å/min) (mV) 5A 2.36 1 150 397 771 29.4 5B 2.35 1 240653 787 29.3 5C 2.37 1 300 821 822 28.6 5D 2.35 1 360 869 782 31.3 5E2.43 1 420 929 829 30.9 5F 2.47 1 500 776 798 30.2 5G 2.32 0.5 120 420694 22.8 5H 2.34 0.5 150 637 728 31.9 5I 2.31 0.5 180 676 753 30.5 5J2.55 3 720 1451 954 29.1 5K 2.64 3 900 1586 927 29.5 5L 2.73 3 1080 1505912 36.6

As is apparent from the data presented in Table 5, the silicon oxideremoval rate increased as the amount of aminopropyl triethoxysilaneincreased, up to at least a concentration of about 500 ppm. Theconcentration of aminopropyl triethoxysilane had relatively littleeffect on the silicon nitride removal rate. Both the silicon oxideremoval rate and the silicon nitride removal rate increased as theconcentration of colloidal silica in the polishing compositionincreased.

EXAMPLE 6

This example demonstrates the effect on the removal rate of siliconoxide and silicon nitride by a polishing composition containing silicaparticles which have been treated with an aminosilane compound.

A TEOS wafer and a silicon nitride wafer were polished with eighteendifferent polishing compositions. Each of the polishing compositionscontained 3 wt. % silica that was treated with aminopropyltriethoxysilane and 1500 ppm 1-hydroxyethylidene-1,1-diphosphonic acid(DEQUEST 2010). The type of silica particles and amount of aminopropyltriethoxysilane that was added to each composition in addition to thezeta potential of the particles are indicated in Table 6.

The silicon oxide removal rate (Å/min) and silicon nitride removal rate(Å/min) were determined for each polishing composition, and the resultsare shown in Table 6.

TABLE 6 Silicon Silicon Oxide Nitride Aminopropyl Removal Removal ZetaPolishing triethoxysilane Rate Rate Potential Composition Silica Type(ppm) (Å/min) (Å/min) (mV) 6A 46 nm colloidal sol 300 761 — gel 6B 46 nmcolloidal sol 600 905 1147 36 gel 6C 46 nm colloidal sol 0 629 — gel 6D50 nm colloidal 300 508 — silicate ion exchange 6E 50 nm colloidal 6001309 816 32 silicate ion exchange 6F 50 nm colloidal 0 297 — silicateion exchange 6G 80 nm colloidal 300 612 — silicate ion exchange 6H 80 nmcolloidal 600 1022 969 40 silicate ion exchange 6I 80 nm colloidal 0 542— silicate ion exchange 6J 150 nm fumed 300 207 — 6K 150 nm fumed 600279 132 34 6L 150 nm fumed 0 179 — 6M 47 nm colloidal 300 398 — silicateion exchange 6N 47 nm colloidal 600 633 805 30 silicate ion exchange 6O47 nm colloidal 0 209 — silicate ion exchange 6P 32 nm colloidal 300 813— silicate ion exchange 6Q 32 nm colloidal 600 1458 597 30 silicate ionexchange 6R 32 nm silicate ion 0 887 — exchange

As is apparent from the data presented in Table 6, treatment ofcolloidal silica particles synthesized using the sol gel method and 46nm, 50 nm, and 80 nm colloidal silica particles synthesized usingsilicate ion exchange were effective in polishing silicon oxidesubstrates, whereas fumed silica particles were not so effective inpolishing silicon oxide substrates. The 32 nm colloidal silica particleswere effective in polishing silicon oxide substrates when a sufficientconcentration of the aminosilane was used to treat the particles.

EXAMPLE 7

This example demonstrates the effect on the removal rate of siliconoxide by a polishing composition containing silica particles which havebeen treated with an aminosilane compound.

A TEOS wafer was polished with seven different polishing compositions.Each of the polishing compositions was adjusted to a pH of 5.1 withnitric acid and contained colloidal silica that was treated withaminopropyl triethoxysilane. The amount of colloidal silica that wasadded to each composition is indicated in Table 7.

The silicon oxide removal rate (Å/min) was determined for each polishingcomposition, and the results are shown in Table 7.

TABLE 7 Silicon Oxide Polishing Removal Rate Zeta Potential CompositionSilica (wt. %) (Å/min) (mV) 7A 10 2677 34 7B 6 2457 36 7C 4 2530 37 7D 22656 32 7E 1 2525 — 7F 0.5 2445 — 7G 0.2 1741 —

As is apparent from the data presented in Table 7, the silicon oxideremoval rate increased as the amount of colloidal silica increased up toabout 2 wt. % colloidal silica.

EXAMPLE 8

This example demonstrates the average particle size and surface coverageof available silanols on treated particles in polishing compositionscontaining colloidal silica particles which have been treated withvarious amounts of an aminosilane compound.

Each of the polishing compositions was prepared as described in Example5. The amounts of aminopropyl triethoxysilane and colloidal silica thatwere added to each composition and the pH of each composition areindicated in Table 8. The size of the treated particles was measuredusing a Malvern HS 3000 after 5 days. The silane left in solution wasmeasured after 5 days by centrifuging the slurry and analyzing thecentrate by derivatizing the primary amines on the aminosilane with the6-aminoquinoly-N-hydroxysuccinimidyl carbamate (AccQ Tag made by Waters)and quantifying using reverse phase HPLC. The amount of silane on thetreated particles was calculated as the difference between the amount ofsilane that was added to the polishing composition minus the amount ofsilane remaining in solution after treatment. The surface coverage isthe amount of silane on the surface of the treated particles divided bythe silanols on the particle surface and is represented as a percentage.The number of silanols on the surface of the particles was determined bymeasuring the BET surface area of the silica (117 m²/g) and using atypical silanol density for colloidal silica of 5 silanols per nm².

The average particle size, amount of silane on the particles, and thesurface coverage of the particles were determined for each polishingcomposition, and the results are shown in Table 8.

TABLE 8 Aminopropyl Average Silane on Surface Polishing Silicatriethoxysilane Particle Size Particle Coverage Composition pH (wt. %)(ppm) (nm) (ppm) (%) 8A 2.36 1 150 50 116 5% 8B 2.35 1 240 49 175 8% 8C2.37 1 300 50 212 10% 8D 2.35 1 360 54 239 11% 8E 2.43 1 420 64 309 14%8F 2.47 1 500 129 309 14% 8G 2.32 0.5 120 50 86 8% 8H 2.34 0.5 150 50 959% 8I 2.31 0.5 180 51 119 11% 8J 2.55 3 720 53 570 9% 8K 2.64 3 900 57687 11% 8L 2.73 3 1080 110 809 13%

As is apparent from the data presented in Table 8, the percent surfacecoverage on the particles increases as the amount of aminopropyltriethoxysilane is increased relative to the amount of silica. Theparticle size remained relatively stable at lower silane concentrations,but increased with higher silane levels relative to the amount ofsilica.

EXAMPLE 9

This example demonstrates the effect on silicon oxide removal rate bythe treated particle size and the value of the silane added divided bythe number of silanols on the surface of particles in polishingcompositions containing colloidal silica particles which have beentreated with various amounts of an aminosilane compound.

Each of the polishing compositions contained 0.3% colloidal silica (45nm) that was treated with bis(trimethoxysilylpropyl)amine, 100 ppm boricacid, and was adjusted to a pH of 3.5 with nitric acid. The amount ofbis(trimethoxysilylpropyl)amine that was added to each composition isindicated in Table 9. The zeta potential and size of the treatedparticles were measured using a Malvern HS 3000. The amount of silaneleft in solution was measured after 2 months by centrifuging thecompositions and analyzing the centrate using LC-mass spectroscopy inthe positive ion mode. The amount of silane on the treated particles wascalculated as the difference between the amount of silane that was addedto the polishing composition minus the amount of silane remaining insolution after treatment. The surface coverage is the amount of silaneon the surface of the treated particles divided by the silanols on theparticle surface and is represented as a percentage. The number ofsilanols on the surface of the particles was determined by measuring theBET surface area of the silica (87 m²/g) and using a typical silanoldensity for colloidal silica of 5 silanols per nm².

The zeta potential, average particle size, surface coverage, and thesilicon oxide removal rate were determined for each polishingcomposition, and the results are shown in Table 9.

TABLE 9 Aminopropyl Zeta Average Silicon Oxide Polishing triethoxysilanePotential Particle Surface Removal rate Composition (ppm) (mV) Size (nm)Coverage (%) (Å/min) 9A 0 −19 49 0 32 9B 10 4 50 3 761 9C 20 18 58 51173 9D 30 21 63 8 1123 9E 120 18 52 27 1153 9F 150 — 52 32 1017 9G 190— 69 38 864 9H 230 39 53 46 696 9I 300 — 141 59 44 9J 400 41 483 81 20

As is apparent from the data presented in Table 9, the silicon oxideremoval rate rapidly increases as the percent surface coverage on theparticles increases to about 5%, and then remains substantiallyunchanged at a relatively high level when the percent surface coverageis increased from about 5% to about 32%, then begins to decrease as thepercent surface coverage on the particles continues to increase. Theaverage particle size remains relatively stable at silane concentrationsof about 200 ppm or less (e.g., a percent surface coverage of about45%), but begins to increase at higher silane concentrations.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. A chemical-mechanical polishing composition for polishing a substratecomprising: (i) a liquid carrier, (ii) an abrasive suspended in theliquid carrier, wherein the abrasive comprises metal oxide particleshaving a surface which has been treated with a compound selected fromthe group consisting of an aminosilane compound, a phosphononiumsilanecompound, and a sulfonium silane compound, and (iii) about 0.0001 wt. %to about 3 wt. % of a corrosion inhibitor.
 2. The polishing compositionof claim 1, wherein the surface of the abrasive has been treated with anaminosilane compound that contains an aminopropyl group.
 3. Thepolishing composition of claim 1, wherein the polishing composition hasa pH of about 4 to about
 7. 4. The polishing composition of claim 1,wherein corrosion inhibitor is about 0.001 wt. % to about 2 wt. %. 5.The polishing composition of claim 1, wherein the polishing compositionhas a pH of about 1.5 to about
 5. 6. The polishing composition of claim1, further comprising an oxidizing agent.
 7. The polishing compositionof claim 6, wherein the oxidizing agent is selected from the groupconsisting of bromates, bromites, chlorates, chlorites, hydrogenperoxide, hypochlorites, iodates, hydroxylamine salts, monoperoxysulfate, monoperoxy sulfite, monoperoxyphosphate,monoperoxyhypophosphate, monoperoxypyrophosphate, organo-halo-oxycompounds, periodates, permanganate, peroxyacetic acid, and mixturesthereof.
 8. The polishing composition of claim 7, wherein the oxidizingagent is present at a concentration of about 0.05 wt. % to about 15 wt.%.
 9. The polishing composition of claim 1, wherein the corrosioninhibitor is an azole compound.
 10. The polishing composition of claim1, wherein the metal oxide particles are colloidal silica particles. 11.The polishing composition of claim 1 further comprising a complexingagent.
 12. The polishing composition of claim 11, wherein the complexingagent is selected from the group consisting of carbonyl compounds,simple carboxylates, carboxylates containing one or more hydroxylgroups, di-, tri-, and poly-carboxylates, carboxylates containing one ormore sulfonic groups, and carboxylates containing one or more phosphonicgroups.
 13. A method of chemically-mechanically polishing a substrate,which method comprises: (i) contacting a substrate with achemical-mechanical polishing composition comprising: (a) a liquidcarrier, and (b) an abrasive suspended in the liquid carrier, whereinthe abrasive comprises metal oxide particles having a surface which hasbeen treated with a compound selected from the group consisting of anaminosilane compound, a phosphononiumsilane compound, and a sulfoniumsilane compound, and (c) about 0.0001 wt. % to about 3 wt. % of acorrosion inhibitor, (d) an oxidizing agent, (ii) moving the polishingcomposition relative to the substrate, and (iii) abrading at least aportion of the substrate to polish the substrate, wherein the substratecomprises at least one layer of silicon oxide or at least one layer ofsilicon nitride, and wherein the substrate further comprises at leastone metal layer, and wherein at least a portion of the substrate isremoved to polish the substrate.
 14. The method of claim 13, wherein themetal layer is selected from the group consisting of tungsten, tantalum,titanium, ruthenium, copper and aluminum.
 15. The method of claim 13,wherein the polishing composition has a pH of about 1 to about
 7. 16.The method of claim 13, wherein the metal oxide particles are colloidalsilica particles.
 17. The method of claim 16, wherein the surface of theabrasive has been treated with an aminosilane compound that contains anaminopropyl group.
 18. The method of claim 13, wherein the oxidizingagent is selected from the group consisting of bromates, bromites,chlorates, chlorites, hydrogen peroxide, hypochlorites, iodates,hydroxylamine salts, monoperoxy sulfate, monoperoxy sulfite,monoperoxyphosphate, monoperoxyhypophosphate, monoperoxypyrophosphate,organo-halo-oxy compounds, periodates, permanganate, peroxyacetic acid,and mixtures thereof.
 19. The method of claim 13, wherein the polishingcomposition has a pH of about 1.5 to about
 5. 20. The method of claim13, wherein the polishing composition has a pH of about 2 to about 4.